The ever increasing amount of air traffic has caused a marked increased in the workload of ATC controllers in high traffic density areas around airports. The Next Generation (NextGen) overhaul of the United States airspace system and the companion Single European Sky ATM Research (SESAR) overhaul of the European airspace system are proposing various trajectory-based mechanisms to ease the pressures on the air traffic management on those continents. Some solutions being suggested include the increased use of onboard Required Time of Arrival (RTA) systems and Airborne Separation Assurance Systems (ASAS) that allow an aircrew limited control of aircraft spacing and separation in areas where ATC personnel face heavy work loads.
ASAS is an onboard system that enables the flight crew to maintain a spacing interval or separation of their aircraft from one or more reference aircraft, and provides flight information concerning surrounding traffic. The ASAS receives traffic information from nearby aircraft using an Automatic Dependence Surveillance-Broadcast (ADS-B) system, an Automatic Dependent Surveillance-Rebroadcast (ADS-R) system or from a ground station using a Traffic Information System-Broadcast (TIS-B). ASAS interval spacing allows the aircrew to achieve and maintain a given spacing with respect to one or more particular reference aircraft. The ATC can either retain the responsibility for aircraft separation in regard to other aircraft or delegate the responsibility. Such systems are useful in dense traffic areas such as the area surrounding an airfield or in oceanic environments where ATC applies procedural separation.
A flight management system (FMS) is an onboard system that may include RTA capability. This RTA capability allows an aircraft to “self-deliver” to a specified waypoint or waypoints of a flight plan at a specified time along a four-dimensional trajectory (latitude, longitude, altitude and time). The RTA system may be used within the context of a Controlled Time of Arrival system to help manage the burden on an ATC system resource. Additional information concerning the use of RTA systems in the cruise phase of a flight plan may be found in Impacts of ATC Related Maneuvers on Meeting a Required Time of Arrival, Paul Oswald, The MITRE Corporation, Egg Harbor, N.J. (2006) and in U.S. Pat. No. 6,507,782, which are hereby incorporated by reference in their entireties.
However, RTA and ASAS systems are self-contained and do not work together. Under the current state of the art, an ASAS system output can conflict with the operation of the RTA system causing frequent and unnecessary flight plan changes which is detrimental to the efficient operation of an aircraft and overtaxes ATC assets.
Accordingly, it is desirable to develop a system that permits an ASAS system to work together with RTA functionality. In addition, it is desirable to enhance the functionality of both the ASAS and RTA systems. Furthermore, other desirable features and characteristics of the present invention will become apparent from the subsequent detailed description of the invention and the appended claims, taken in conjunction with the accompanying drawings and this background of the invention.